Please help my Tyson!

My Tyson is very sick. He has lost 20 lbs in the last 3-4 weeks and refuses to eat anything. With the tests the Vet has performed they can't figure out what exactly is wrong. We have a good idea of what his problem could be but with the tests and surgery it will be very expensive. I refuse to let money come between me and the love of my life! He is my very best friend and my son. I can't imagine life without him. Thank you in advance for anything you can do to help.

-Donnie